A structural dynamics model for how CPEB3 binding to SUMO2 can regulate translational control in dendritic spines.

Area of Science:

• Neuroscience
• Molecular Biology
• Biophysics

Background:

• The prion-like RNA-binding protein CPEB3 regulates local translation in dendritic spines.
• CPEB3 monomers repress translation, while CPEB3 aggregates activate translation of target mRNAs.
• Unregulated translational activation by CPEB3 aggregates poses a challenge for synaptic plasticity.

Purpose of the Study:

• To computationally model the complex structure between the CPEB3 RNA-binding domain (CPEB3-RBD) and SUMO2.
• To elucidate the mechanism by which SUMOylation regulates CPEB3's RNA-binding affinity and activity.
• To explore the role of the CPEB3/SUMO2 interplay in synaptic structural changes and long-term memory formation.

Main Methods:

• Computational modeling of the CPEB3-RBD/SUMO2 complex.
• Free energy calculations to assess interaction effects.
• Integration of computational findings with existing experimental data on CPEB3 SUMOylation.

Main Results:

• Free energy calculations indicate that SUMO2 binding allosterically amplifies CPEB3's RNA-binding affinity.
• The model suggests a shift in mRNA binding from deSUMOylated CPEB3 aggregates to SUMOylated CPEB3 monomers.
• This interplay explains how local translation bursts in synapses are silenced post-stimulation.

Conclusions:

• The CPEB3/SUMO2 interaction is a key regulatory mechanism for controlling local translation at synapses.
• SUMOylation dynamically modulates CPEB3's RNA-binding state, influencing synaptic plasticity.
• This molecular interplay provides insights into the mechanisms underlying long-term memory formation.